Timeline Activities: syncing multi-select fields

We have added support for dropdown (Picklist) but multi-select in dropdown is not supported as of now.
We can not confirm now when this feature will be available.

Thanks Sandeep + Lila -- I'd like to focus on the drop-down option. (We currently don't have a need for multi-select syncing.)

When in the configuration panel for an activity > + Field - I have (text, date, number, checkbox) available as option. I thought 'text' may be the best choice to map to a dropdown, but when in the activity sync configuration panel, the corresponding drop-down field I'd like to map to doesn't appear as an option.

I had my SFDC admin confirm - we don't see any permission differences between the dropdown field I want to map to and the text fields currently shown. The only thing we thought it might be, is text vs dropdown.

Related community post: https://community.gainsight.com/gainsight/topics/adding-fields-to-timeline-activities

Bumping this up to see if mapping functionality is available for custom drop-down (picklist) fields.  I am unable to access this when starting with a 'text' field.

Yes, mapping functionality work for picklist. But make sure your picklist field has "Restrict picklist to the values defined in the value set" property is unchecked.
Refer this link